SMG Gearboxes

[_Nathan_]

Thank you.

Did you weld seperate take offs for the pipes in to the box or adapt the filler hole and sump plug to accept return and pump feed respectively, trying to weigh up the best way of doing it versus trying to do it cheaply

[NZ_M3]

Hi,

Hi- NZ_M3 - I do not agree with what the ''Americans' have to say
on this issue, sorry.

Fair enough - I don't agree with everything they have to say about the M3s - but majority of them know more about the SMG system than you do I must say. But I'll entertain.

If I remember correctly you also dismissed the rear turret reinforcement
rings from the Z3, saying they would make no difference ?

And I still say they make no difference - a stress induced failure will take time - time will prove me right that if you run a full coilover setup on the rear of the E46 coupe chassis without a full cage or the likes to spread the load then it's only a matter of time before the rear shock tower tears itself apart.

The SAC Clutch is a bad design, go ask any E39 M5 owner or Forum
on SAC standard clutch which is the same poorly designed component.

I agree - I never said the Self Adjusting Clutch was a good design (made worse by the Clutch Delay valve that BMW insists on putting in their cars) - I am simply saying your technical explanation is incorrect ... the forums are for sharing information, and I am simply pointing out inaccuracies that you are putting across. For example your explanation below of how the Self Adjusting mechanism works - it couldn't be further from the truth

The wear in the clutch is adjusted via a nylon strip within the SAC
pressure plate, so as to try and compensate for the wear in the disc.
This was designed to make the engagement travel of pressure plate
to clutch the same as the disc wears.

The self adjusting mechanism works off a spring and ramp ring design - i.e. it rotates in or out to compensate for the wear:

Here it is directly from the manufacturer - as I said, the OEM clutch pack is made by LuK

Since clutches are subject to wear during use in the vehicle, LuK, as the first clutch manufacturer, put a great deal of effort into developing a type of wear compensation system for the clutch, and put it in production in 1995. The self-adjusting clutch SAC uses a load sensor (sensor-diaphragm spring) to activate its wear compensation by turning a ramp ring. This compensation mechanism has made it possible to decrease operating loads. The compensation for the clutch wear has also made it possible to increase the clutch service life by about 1.5 times without any significant change in the operating load over the service life. The wear adjustment system of the SAC – consisting of the sensor-diaphragm spring (load sensor) and the deep-drawn steel adjuster ring – is characterized by very high functional precision. Since a harmonic operating load curve is required in addition to comfortable clutch operation, the SAC was created with the capacity to be tuned to specific vehicle characteristic curves. One of the mechanisms that makes this possible is the compensation spring, which can generate the flatter characteristic curves that are frequently desired.
The newly developed SAC II.

provides a further optimization of the system. Here, the load sensor is not comprised of a second diaphragm spring, but rather of the sensor fingers formed from the main diaphragm spring and special tangential leaf springs with a decreasing characteristic curve.

Of course as these two components wear and the SAC tries
to keep the distance bewteen disc and flywheen the same the
travel distance of the hydraulics increases as the disc is worn.

Once a slight mis-alignment starts to ocurr due to wear etc, then
the acctuators still function on pulse signal, inputs etc,
and the pump is told shift, it has no way to compensate for any
slight mis-alignment or wear 'ie slack' in the system.

On a manual car the SAC clutch adjustment when worn is
to a degree compensated by the driver inputs, and the shift
pattern to an extent can be altered to suit.

Wrong again .... If what you are saying is true, then as the clutch disc wears the distance required to 'disengage' (or open) the clutch should be shorter (i.e. it takes less pedal travel to disengage the clutch as there's less material between the pressure plate ring and the flywheel due to the clutch plate wearing down). The opposite would be true when closing the clutch or engaging the clutch as there's a larger space for take up - that is why when clutch wears out the clutch pedal take up point (or bite point) is higher in a traditional 3 pedal manual car.

I can assure you that the hydraulic clutch slave actuator pushes the clutch in (to disengage) the same distance everytime through out the whole life of the clutch - the software initialisation only adjusts the take up point (i.e. to engage the clutch) ...

Here directly from the SMG training manual:

The Clutch Slave Cylinder is an innovative and new feature of the SMG II. The component consists of a slave cylinder with an integrated sensor housing. The sensor termed PLCD (Permanent Linear Countactless Displacement) measure clutch release travel

Shimmy- I do not think that re-programming the Gear box ECU/Software
would make much difference once the clutch has worn past a certain
point, go to the Hewland website explains a lot about gearboxes.

Again wrong as above.


I am aware that Sachs has brought out a new clutch pack that works on both manual and SMG vehicles - I've yet to try it or read the specs on it - but my suspicion is that it has an uprated friction plate rather than an increased pressure plate clamping force. But I'll need to read the specs to be sure.

[The Gorilla]

Hi,

Nathan- on the Gearbox oil cooler in and out feeds
I used the bottom drain plug for the feed out,
and the side plug for the return.

Banjo fitting for feed out, with the lug cut down to
keep the fitting as close to the box as possible,
and a new blanking bush for the side, with a Goodridge alloy T
so that I could run my Gearbox temp sensor as well.

NZ_M3- Your entitled to your views and opinions, but please
read and understand what I have said.

By the way I beleive the manufactures of the Titanic said it
was, quote, '' Unsinkable''.

Regards,

The Gorilla.

[shimmy]

dear Gorilla and NZ_M3

i do find both of your threads and posts very interesting and full of technical info that most of us here, and tbh most of the BMW specialists we know would not understand

however you both seem to constantly disagree with each others techinical opinions on nearly every subject even subjects that can only have one answer

now i am not a mechanic or even a person with car knowledge more than a few skils like changing brake pads and wheels and occassionally a disc or two, but i am qualified as a Project Manager and understand when i am being fed bullshit on a monumental scale.

So for my peace of mind and so i get some sleep without worrying if my rear turret is gonna split or if my chassis is gonna twist or if my gearbox and clutch is gonna piss itself all over the floor can which ever one of you that is guessing (note my careful choice of words) please stop and let the other tell us the truth!

[_Nathan_]

Thanks very much - that was the answer I was hoping for (as it doesn't involve too much labour!).

[glendog74]

dear Gorilla and NZ_M3

i do find both of your threads and posts very interesting

I'm off to bed... :whistle:

[AlexGTT]

dear Gorilla and NZ_M3

i do find both of your threads and posts very interesting and full of technical info that most of us here, and tbh most of the BMW specialists we know would not understand

however you both seem to constantly disagree with each others techinical opinions on nearly every subject even subjects that can only have one answer

now i am not a mechanic or even a person with car knowledge more than a few skils like changing brake pads and wheels and occassionally a disc or two, but i am qualified as a Project Manager and understand when i am being fed bullshit on a monumental scale.

So for my peace of mind and so i get some sleep without worrying if my rear turret is gonna split or if my chassis is gonna twist or if my gearbox and clutch is gonna piss itself all over the floor can which ever one of you that is guessing (note my careful choice of words) please stop and let the other tell us the truth!

Very succinct, yet still diplomatically expressed Shimmy.

I'm off to bed as well! :smt039

[The Gorilla]

Hi,

Shimmy- my views are always expressed from first hand
experince and things that have happened to my cars.

Just for the record, a Lightweiight flywheel [12lbs] with
a Sachs Uprated Clutch Disc and cover was fitted to my Car, CSL.

It was dreadful, so the Gearbox ECU was reprogramed with the
latest version of the software, no change.

Then the SMG pump fluid was drained the system was flushed and
refilled. No change still would not engage properly, the upshifts and
downshifts were all hit or miss etc.

So the Lighter flywheel was removed, the dual mass refitted, with
the Sachs clutch, and the car has its moments but by and large its
OK. Can still get a small 'slur' now and then without sport or DSC off.
Now done around 1500 hard miles, its only used for Track days and the
odd local blast when trying things out, and its been OK.

I also have a E30 M3 with a CSL S54 engine Motec M800 and Drenth sequential Gearbox running a Dual disc 184MM Clutch with a 10lb
alloy flywheel, and a central clutch cylinder, which on the 'flatshit'
makes the SMG feel very slow.
This car does not run the 'E,Gas' or Fly by wire, but is running a throttle
cable/Linkage, which out of slower bends does allow a quicker pick up.
The S54 without the dual mass flywheel is far more responsive at lower revs
that its a shame that the SMG will not function correctly
with a lighter flywheel.

I did look into lighter dual mass flywheel in steel, but the savings
were not more than around 2-3 Kg which was not worth the costs.

Pectel have now developed a plug and play standalone for the S54 which
has been mapped specifically for the E.Gas, fly by wire, and in therory
will always have the throttle and air optimised as its rev matched and
picking up signals from engine load etc.
Interestingly they do not recommend SMG on a Car running this system.

Regards,

The Gorilla.

[NZ_M3]

I also have a E30 M3 with a CSL S54 engine Motec M800 and Drenth sequential Gearbox running a Dual disc 184MM Clutch with a 10lb
alloy flywheel, and a central clutch cylinder, which on the 'flatshit'
makes the SMG feel very slow.

why Hell ... you win Gorilla ... I can't compete with somebody with a car like that :thumbs::thumbs: That's awesomeness right there ... even more awesome if you did the work yourself :supz:

Would love to see some pictures of that beast !!!

How much did the drenth sequential cost? I've always wondered if it'd take much to convert the SMG in the CSL to the Drenth sequential (for track use of course, one'd be almost crazy to drive that gearbox on the road).

Oh and just for the record so that I am not seen as talking out of my ass ... I am not a mechanic by trade, but am self taught. Mostly to do with Hondas, but the basics are all much the sameness. I've personally done and completed 2 x auto to manual conversions, 2 engine rebuilds, numerous wiring and mechanical jobs on hybrid motor swaps for Hondas (much harder than it sounds) and am competent at changing a clutch on my own in a Honda (I've done it in record time of just under 3 and a half hours by myself on a B series with the engine in the car - dealerships quote 7 hours for the job) - but that's just monkey work I suppose.

I gather most of my knowledge on the M3 from personal experience and from reading training manuals when available - most other sources and knowledge I've built up over the years from reading forums and having 3 close friends who are master BMW mechanics - so what I don't know I just ask.

[_Nathan_]

Drenth is about £10k+VAT, but I can't see how you could get ignition cut for flat shift without a new ECU and therefore loom.

Believe you also need to mess about with starter motor too as the Drenth bell housing moves it I think.

Would love a Drenth + paddle shift mechanism. One day...

[NZ_M3]

Drenth is about £10k+VAT, but I can't see how you could get ignition cut for flat shift without a new ECU and therefore loom.

Believe you also need to mess about with starter motor too as the Drenth bell housing moves it I think.

Would love a Drenth + paddle shift mechanism. One day...

Cheers for that.

Yeah I figured to put in a Drenth you'd have to go aftermarket ECU and disable the traction control or run a different software perhaps?

We can always dream !! If only money was no object :hahaha:

[_Nathan_]

Motec will do traction with variable slip so that could be covered if you wanted. You'd also have to consider motorsport ABS units.

Basically a complete rewire of the car with a new loom, not the work of an afternoon!

Approx 50 hour inspection interval too, expensive business.

Occasionally you see second hand DG400s come up in europe but the actual box price isn't quite so significant when you add every thing needed up together.

[The Gorilla]

Hi,

NZ_M3 - There are no winners, we are all just Petrol Heads
spending our hard earned cash on metal boxes that have
components in them that every now and then seem to fail.

If I ever get to NZ to see a colleague on South Island, Conrad,
who races a E30 M3 with 2.5 S14 then the beers are on me.

It was about a 2 year build project on and off, did all myself
except the Paint Sparying and the MOTEC M880 loom, ECU Etc.

Its a S54 CSL running Motec M880 ECU, Plasma Coils, Bosch Ignition
Drivers, Vanos deleted, Dry Sumped with Oil/water heat exchangers.
twin 60mm exhaust with side exit and no Cats.
Drenth 6 speed DG400 Sequential, with DTM Alloy Cased Rear 3.73 LSD,
ZM3 Coupe rear arms with Bilstein Alloy Remote adjust Coil Overs,
fronts are 92 DTM Titanium Uprights, with Remote adjust 2 way coil
overs, Intrax Camber plates, Grp A Adjustable Front Arms, front and
rear ARB's are Cockpit adjustable blades, Manual 2.3 lock to lock rack,
and its runs on 92 DTM 9X18 Centre locks etc.

Shell is full weld in Chromoloy Cage with Carbon wings, bonnet, boot,
Polycarbonite windows, heated front screen,carbon door cards, full
flat floor underneath in Carbon, and it weighs wet without driver 1075kgs.

Its making about 370 BHP, rev limited to 8350, as its turned down a bit
just for engine longtivety, hopefully.

The hardest problem was cutting all the bulkhead and getting
it right so that the S54 engine sits about 70mm further back
than when others have done similar 6 cylinder conversions into
the E30 M3.

I learnt a lot when I did a road E30 M3 with a S50B32/ 6 speed box, which
I have just sold to a Guy in Hong Kong, it was a RHD build.

I will post some pics up shortly, if I can get them to load.

Regards,

The Gorilla.

[AlexGTT]

Would be very interested to see pictures of those motors Gorilla.:thumbs:

[Bealo]

Now that sounds like a hell of a car and a lot of fun on track.... :thumbs: